Why does cyanosis occur in children with tetralogy of fallot

Peripheral access was established, first with a tibial intraosseous catheter and then with a peripheral intravenous line; she received a normal saline bolus, a blood culture was drawn which remained negative , and a dose of ceftriaxone was administered.

A rapid sequence intubation was performed with etomidate and vecuronium. The child was successfully intubated with no complications. Chest X-ray could not view the aortic knob or descending aorta well and could not rule out a right-sided aortic arch Figure 1. With these findings and the severity of her illness, the decision was made to transfer the patient to a tertiary pediatric medical center. On arrival, a brief transthoracic echocardiogram TTE was concerning for Tetralogy of Fallot with critical pulmonic stenosis versus atresia.

She received an additional normal saline bolus, sodium bicarbonate, midazolam, and fentanyl. On attempts to draw labs, her blood was noted to be very dark and hyperviscous, clotting almost immediately. The infant was admitted to the pediatric intensive care unit PICU for further stabilization and started on a prostaglandin drip with the hope of reopening her ductus arteriosus to increase pulmonary blood flow.

Repeat TTE confirmed the diagnosis of Tetralogy of Fallot with severe pulmonary stenosis, hypoplastic main and branch pulmonary arteries, right-sided aortic arch, and small secundum atrial septal defect Figure 2. Over the next several hours, she continued to decompensate with worsening hypoxia and hypotension despite phenylephrine infusion, fentanyl infusion, and aggressive fluid resuscitation. Pediatric cardiothoracic surgery evaluated the patient, and the decision was made to perform an emergent Blalock—Taussig BT shunt.

The patient underwent modified BT shunt with a 3. There were no complications, and she returned to the PICU for post-op recovery. Daily TTE demonstrated normal biventricular function without pericardial effusion, as well as flow across BT shunt and through both branch pulmonary arteries.

By post-op day two, she was tolerating oral feeds. She was discharged home on post-op day four with The plan is to take the infant back to the operating room to perform a complete repair with a transannular patch at 4—6 months of life.

Tetralogy of Fallot is estimated to occur in as many as 1 in live births, making it the most common cyanotic congenital heart disease [ 3 ].

Classically, infants are diagnosed after birth but prior to discharge from the nursery, although in utero diagnosis is also possible now [ 4 ]. Infants are often noted to be cyanotic, have an audible heart murmur, and have decreased oxygen saturation on pulse oximetry testing. Screening for congenital heart disease is endorsed by the American Academy of Pediatrics among other professional societies and is even required by state law in many regions [ 5 ].

This is because congenital heart defects are the leading cause of infant mortality from birth defects, and early recognition and intervention can allow an affected infant to live well into adulthood [ 3 , 6 ]. Screening is aimed at diagnosing patients with critical congenital heart defects, thus smaller defects are likely missed at an increased frequency. Some patients with Tetralogy of Fallot initially do not have a large degree of right ventricular outlet obstruction, allowing them to oxygenate more effectively.

When missed by screening, patients with Tetralogy of Fallot typically develop increasing hypoxia as their ductus arteriosus closes and they have progressive right ventricular outlet obstruction. A rapid reduction in blood flow across the right ventricular outlet could be one of several explanations for the isolated symptom of cyanosis observed in this case. If undiagnosed, the child can present critically ill and develop complications related to their condition ranging from respiratory distress to death.

Cyanosis can be more difficult to detect in dark-skinned individuals and is dependent on the absolute concentration of deoxygenated hemoglobin [ 7 ]. It can be useful to differentiate between central and peripheral cyanosis, also called acrocyanosis. Peripheral cyanosis is present in the distal extremities; it can be physiologic, appearing wherever there is a large arteriovenous oxygen gradient that develops with slow blood flow through distal capillary beds [ 8 ].

The etiology can be innocent, related to cold environmental temperatures, or other external factors. Any cause of cyanosis must be taken seriously, however, as peripheral cyanosis can also be caused by severe systemic illnesses such as sepsis, polycythemia, or hypoglycemia.

There is also less blood traveling to the lungs because the pathway is narrowed. This leads to less blood becoming red, oxygen-rich blood. Sometimes, infants with TOF have pulmonary atresia , where the pulmonary valve is completely sealed off. Right ventricular hypertrophy hi-PER-truh-fee , which is a thickening of the muscular wall of the right ventricle.

The thickened wall can contribute to blocking the flow of blood through the pulmonary valve, which allows blood from the heart to flow into the lungs. An " overriding aorta ," which means the artery that carries high-oxygen blood to the body is out of place and arises above both ventricles, instead of just the left ventricle, as in a healthy heart.

This allows some blood that is low in oxygen to flow into the aorta and out to the body, instead of to the pulmonary artery, which would normally take it to the lungs to pick up oxygen. Other signs include: heart murmur fussiness tiring easily difficulty breathing rapid heartbeat palpitations fainting "clubbing," where the skin or bones around the tips of fingers are widened or rounded What Causes Tetralogy of Fallot TOF?

Most of the time, a child with TOF doesn't have any other birth defects. Doctors might do several tests to find out if a baby has tetralogy of Fallot and to get more details about the baby's heart and blood vessels, including: pulse oximeter : a small sensor that clips onto the fingertip, toe, or ear and measures how much oxygen is in the blood.

In many newborn nurseries, all babies have a pulse oximeter test before going home to make sure that their oxygen level is normal. It records the motion of the blood through the heart and can measure the direction and speed of blood flow. Sometimes, a device is inserted into the heart or blood vessels through the heart catheter. The two surgical options are: Complete repair: The surgeon widens the passageway between the right ventricle and the pulmonary artery to improve blood flow to the lungs.

Next, it travels through the tricuspid valve to the right ventricle of the heart. Oxygen-rich red blood comes back to the left upper chamber of the heart left atrium from the lungs. Then it passes through the mitral valve and into the left ventricle of the heart. Some children with TOF may only have slightly lower than normal oxygen levels in their blood.

Other children with TOF will have low oxygen levels in their blood. These children have bluish skin. This is from the low oxygen levels in their blood. Genes and family history may play a part in TOF. It may also be caused by Down syndrome or 22q Most of the time, this heart defect occurs by chance, with no cause.

Symptoms can show up a bit differently in each child. The most common symptom is a bluish color of the skin, lips, and nail beds. This may come on in sudden spells, called TET spells. It happens when blood oxygen level drops quickly. During the spell, babies may have a hard time breathing. They may also be tired and fussy. In the most severe cases, they may lose consciousness.

The symptoms of TOF may be similar to symptoms caused by other problems. Editorial team. Tetralogy of Fallot. The classic form includes four defects of the heart and its major blood vessels: Ventricular septal defect hole between the right and left ventricles Narrowing of the pulmonary outflow tract the valve and artery that connect the heart with the lungs Overriding aorta the artery that carries oxygen-rich blood to the body that is shifted over the right ventricle and ventricular septal defect, instead of coming out only from the left ventricle Thickened wall of the right ventricle right ventricular hypertrophy Tetralogy of Fallot is rare, but it is the most common form of cyanotic congenital heart disease.

The cause of most congenital heart defects is unknown. Many factors seem to be involved. Factors that increase the risk for this condition during pregnancy include: Alcoholism in the mother Diabetes Mother who is over 40 years old Poor nutrition during pregnancy Rubella or other viral illnesses during pregnancy Children with tetralogy of Fallot are more likely to have chromosome disorders, such as Down syndrome, Alagille syndrome, and DiGeorge syndrome a condition that causes heart defects, low calcium levels, and poor immune function.

Symptoms include: Blue color to the skin cyanosis , which gets worse when the baby is upset Clubbing of fingers skin or bone enlargement around the fingernails Difficulty feeding poor feeding habits Failure to gain weight Passing out Poor development Squatting during episodes of cyanosis.

Exams and Tests. A physical exam with a stethoscope almost always reveals a heart murmur. Outlook Prognosis. Regular follow-up with a cardiologist is strongly recommended. Possible Complications.